1. Field of the Invention
The present invention relates to weapon sighting devices in general, and more particularly to sights for use on firearms.
2. Related Art
Over the years, sighting devices have been developed to permit the user of small arms such as rifles, muskets, revolvers, shotguns, machine guns, and pistols, to align the weapon accurately relative to a target such that a projectile fired from the weapon may hit the target reliably.
Such sighting devices, or gun sights, may be seen as falling into two broad groups, namely, “active” and “passive” sights. Active sights typically illuminate the target with some form of radiation, and rely on a reflection of the radiation from the target to ensure correct alignment of the weapon with the target. An example of an active sight is commonly referred to as a laser sight. A laser sight generates a beam of laser light that is projected onto the target field such that the light beam actually illuminates the point of impact at a certain range. Such sights are highly effective in certain conditions, but suffer from a number of disadvantages. For example, depending on conditions the target may be able to see the light beam or its reflection, and when there are multiple weapons illuminating the same target it may become difficult for each user to know which reflection is associated with which firearm.
Passive sights typically rely on ambient illumination of the target and include the familiar open sights or “iron sights” comprising a front sight (e.g., a dispart sight such as a blade or tang disposed at the front end of the barrel of the weapon) and a rear sight (e.g., a complementary notch, groove, or circular aperture disposed at the rear end of the receiver or slide of the weapon). Passive sights also include “telescopic” sights that use a reticle, such as a set of adjustable “crosshairs” disposed inside the optics of a magnifying or non-magnifying telescope.
One type of passive sight, commonly referred to as a reflex sight, uses a refractive or reflective optical system to generate a collimated beam of light that is projected toward the user to create an illuminated reticle. The resulting plane wave seen by the user appears as a small, approximately circular disc of light that is focused at infinity. In a standard open reflex sight this illuminated reticle is projected such that it is superimposed over the field of view observed through the sight. This allows the user to see the target field through the sight as well as the illuminated reticle (e.g. an illuminated red dot) in one eye simultaneously. This gives the user a theoretically parallax-free image of the reticle, superimposed over the field of view through the sight.
Another type of passive gun sight that is particularly advantageous in close combat and similar situations is often referred to as an “occluded eye gun sight” (OEG). A common form of an OEG is essentially a closed reflex sight, in which the field of view through the sight is occluded such that the user sees the illuminated dot of the reflex sight superimposed over a blank background instead of an open field of view through the sight. When using such an OEG, the user's dominant eye is positioned behind the OEG and focused on the illuminated dot. That dominant eye is blocked or occluded by the OEG such that it does not see the target and instead sees only the illuminated dot.
The user's other eye is not obscured by the OEG and is focused on the target. When aiming the firearm, the user's brain superimposes the illuminated dot seen by the occluded dominant eye onto the target seen with by the user's other eye such that if the firearm is properly oriented the illuminated dot appears to the user to be projected onto the target. Effective use of an OEG requires both of the user's eyes, sometimes referred to as binocular vision. One example of a commercially available OEG for use on rifles, handguns, and grenade launchers, is the Trijicon “Armson O.E.G.®.” OEGs have significant advantages over other types of sighting devices in high-stress and close combat situations that require extremely fast target acquisition without compromising the user's overall situation awareness.
Like other prior art OEGs, the Armson O.E.G. mounts on either the side or the top of the receiver of the weapon. However, neither of these arrangements is a natural location for binocular viewing, and mounting an OEG on the top of the receiver interferes with the use of conventional open sights. These mounting arrangements also change the balance of the firearm, require the use of a custom or modified holster, and require the use of a substantially modified shooting position depending on which sighting device is being used. The term OEG may be used herein to refer to a sight designed to be used as an occluded eye gun sight or to a standard reflex sight that may be occluded such that it can be used as an occluded eye gun sight.
Accurate use of all firearms requires extensive repetitive use. However, the use of live ammunition for training is expensive and requires access to a shooting range. Dry firing—firing the weapon without ammunition—may be an effective training exercise because it allows for the repetition needed to develop muscle memory, and the user may practice in a wide range of locations and situations. However, absent highly specialized and expensive training simulation systems, dry firing does not provide real-time user feedback regarding the accuracy of the practice “shot.” This lack of user feedback significantly undermines the value of dry fire training.
A long felt but as yet unsatisfied need therefore exists for an improved sighting device that overcomes the disadvantages of prior art sighting devices and provides for improved dry fire training.